A. Field of the Invention
The present invention relates to a vibration attenuating spring and a damper mechanism using the vibration attenuating spring for attenuating twist vibrations.
B. Description of the Related Art
In a vehicle, a damper mechanism is typically interposed between an engine and a transmission for absorbing torque variation of the engine. The damper mechanism may be part of a clutch disc assembly or a flywheel assembly of a clutch mechanism. The damper mechanism usually includes an input member and an output member which are rotatable relative to each other, spring members such as coil springs for limiting the rotation of the two members with respect to each other, and a friction generating mechanism for generating a friction for attenuating the vibrations when the two members are rotated relative to each other. Alternatively, instead of the friction generating mechanism, it is possible to use a viscous resistance generating mechanism with the spring members for generating a viscous resistance to attenuate the vibrations. The viscous resistance generating mechanism may generate a large resistance in comparison with the friction generating mechanism.
The above-described mechanism using the viscous resistance generating mechanism requires a sealed fluid chamber for containing fluid used with the viscous resistance generating mechanism. Therefore, a reliable seal configuration is necessary. Also, since two kinds of mechanism, the spring members and the viscous resistance generating mechanism, are required for optimal operation, the structure is complicated and expensive to manufacture.